<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            display: flex;
            /*justify-content: flex-end;*/
            /*justify-content: flex-start;*/
            /*justify-content: center;*/
            /*justify-content: space-around;*/
            /*justify-content: space-evenly;*/
            justify-content: space-between;
            width: 90%;
            height: 600px;
            background-color: skyblue;
        /*    如果希望子元素数量太多放不下，能换行，*/
            flex-wrap: wrap;
        }
        span{
            width: 100px;
            height: 100px;
            background-color: greenyellow;
        }
    </style>
</head>
<body>
<!--flex-direction-->
<div class="">
    <span>1</span>
    <span>2</span>
    <span>3</span>
    <span>4</span>
    <span>5</span>
    <span>6</span>
    <span>7</span>
    <span>8</span>
    <span>9</span>
    <span>10</span>
</div>
</body>
</html>